Sum of square of first n even numbers | Efficient C # method to find sum of square of first n even numbers . ; driver code
using System ; class GFG { static int squareSum ( int n ) { return 2 * n * ( n + 1 ) * ( 2 * n + 1 ) / 3 ; } public static void Main ( ) { Console . Write ( squareSum ( 8 ) ) ; } }